Evacuating and gas charging apparatus with movable support and vacuum pump carried thereon



Aug. 21, 1951 Q DE GROAT 2,565,298

. EVACUATING AND GAS CHARGING APPARATUS WITH MOVABLE SUPPORT AND VACUUM PUMP CARRIED THEREON Filed Feb. 7, 1946 mm OPERHTEU 67 0/; DIFFUSION PUMP 7'0 8 .SURPLY mac/(m0 PUMP;

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, InvenTor' Charles T. DeGroaT m a M His flffor'ngg Patented Aug. 21, 1951 EVACUATING AND GAS CHARGING APPA- RATUS WITH MOVABLE SUPPORT AND VACUUM PUMP CARRIED THEREON Charles T. De Groat, Ballston Lake, N. Y., assig nor to General Electric Company, a corporation of New York Application February '7, 1946, Serial No. 646,130

My invention relates to evacuating apparatus and more particularly improved evacuating apparatus which is particularly adapted for the manufacture of electric discharge devices.

In the making of electric discharge devices on automatic machinery, it is common practice to provide a, movable support having a, plurality of stations movable therewith and each including a compression fitting for supporting one of the. devices to be evacuated. The various compression fittings are each individually connected with an evacuating system. A device is loaded or connected with the compression fitting at one sta-. tion and undergoes a succession of steps in the evacuating process in each of a plurality of positions occupied by each of the stations during a complete cycle of operation of the machine. In accordance with the teachings of my invention, I provide improved apparatus of this character in which the volume of the system which is subjected to atmospheric pressure during. loading of the device is kept at a minimum. The system is also well adapted for utilizing vacuum pumps of the diffusion type employing an organic. liquid. such as one of the artificial or natural oils, and in which the fine vacuum pumping devices are carried by the movable support. of the apparatus. My invention also contemplates an improved system for automatically charging the evacuated device at a particular station of the movable part of the apparatus to a predeter mined gas pressure, provided the desired degree of evacuation has been accomplished during operation of the equipment at the preceding positions occupied by that station.

It is an object of my invention to provide new and improved evacuating apparatus particularly adapted for continuous manufacture of aplurality of evacuated devices. 1

It is another object of my invention to provide new and improved automatic exhausting apparatus.

It is still anotherobject of my invention to provide new and improved apparatus for exhausting and chargin with gas to a predetermined pressure electric discharge devices or the like.

My invention will be better understood as the following description proceeds, reference being had to the accompanying drawing, and its scope will be pointed out in the ap ended claims. In the drawing, Fig. 1 is an elevational View, partially in section, illustrating a portion of an automatic exhaust machine and gas charging apparatus em bodying my invention, Fig. 2 is an enlarged elevational view, partially in section, of a portion of Claims. (o1. 22s 2o.1)

H the apparatus shown in Fig. l, and Fig. 3 is a plan view illustrating the stationary valve plate and conduit systems of the machine.

Referring now to Fig. l of the drawing, I have shown my invention embodied in an automatic exhaust machine for electric discharge devices having a plurality of stations supported from a movable support or turntable I which is rotably mounted on a stationary support 2. Each of the stations is identical and in the interest of simplifying the drawing only one has been illustrated. In a practical machine embodying my invention, sixteen stations are employed. As illustrated in the drawing, the station includes a vacuum pump, designated generally by the numeral 3, which is supported by a suitable bracket 4- from a peripherally extending flange 5 carried by the table I. The pump 3, may to advantage be of the type employing a vapor of an organic fluid, such as a natural or synthetic oil. The particular pump illustrated is of the type known as a two-stage vertical pump and includes vertical conduits or stacks 6 and 1. The stack 6 provides at its upper end the intake or low pressure side of the pump. As clearly illustrated in Fig. 2, the upper end of the stack 6 supports a compression fitting assembly for supporting the devices to be evacuated and a solenoid valve which controls the communication between these devices and the interior of the pump.

Referring now to Fig. 2, a conduit 8 is supported from the upper end of th stack 6 by a pair of threaded fittings 9 and it. The fitting Ill is secured to the stack 6 and provides a support for a valve. seat II which may be formed of metal or a resilient material such as one of the synthetic rubbers. The fitting 9 is threaded into the fitting l0 and bears against a flange [2 formed on the lower end of the conduit 8 to hold the conduit and the valve seat assembled within the fitting In. The port I3 of the valve seat is normally closed by a valve member it having a stem l5 extending upwardly into the conduit 8 and surrounded by an armature or actuating member [6 of magnetic. material. The member I5 is adapted to move between a stop provided at one end of the stem I5 by the valve member I4 and a stop provided at the other end by a nut or other projection H.

An operating coil I8 for the armature I6 is supported on the exterior of the conduit 8 by a disk-like member 19 which is secured to the conduit by a set screw 20. A cover member 2| for the solenoid is provided and completes a low loss magnetic circuit for the coil Hi. It will be apparent from this description that the conduit 8 should be formed of nonmagnetic material, such as nonmagnetic stainless steel or brass, so that the flux produced by energization of the coil I8 is not shunted by the conduit and is effective to raise the actuating member into engagement with the stop I! and to lift the valve member [4 from the valve seat.

A compression fitting assembly is provided at each station of the apparatus and, as illustrated, each includes a generally cylindrical body 22 having an integral bracket 22' which is secured to the conduit 8 just above the housing 2| of the solenoid. The body 22 is provided with a central bore 23 and a'counterbore 24 at its upper end to receive a compression gasket 25 which may be formed of rubber and which is adapted to be compressed, by means of a flanged member 26, into engagement with a conduit or stem received within the bore 23. As illustrated in the drawing, the device to be evacuated is the envelope 2'! of an electric discharge device and includes a tubulation 28 extending through the gasket 25 and into the bore 23. The body 22 is externally threaded at its upper end to receive an internally threaded nut 29 of the compression head which, as illustrated, is recessed to receive the member 26. In order to render it possible to apply considerable pressure to the gasket 25 with the application of a relatively small force to the nut 29, a ball bearing 39 is positioned between the flange of the member 26 and a bearing member 3| secured to the inner end wall of the nut 29.

The bore 23 communicates with the conduit 8 and the intake of the vacuum pump 3 by a conduit 32 connected with a cap 34 sealed to the upper end of the conduit 8.- In order to provide a receptacle for pieces of glass and other foreign matter which may drop from the bore 23, the body 22 is counterbored from its lower end as illustrated at 35. This matter may be removed periodically by removing the closure member 36 which is threaded into the lower end of the bore 35.

In order to cool the compression head as well as the solenoid and the upper portion of the vacuum pump, the member 23 is provided with passages 31 through which cooling fluid is circulated. As illustrated in Fig. 2, an inlet conduit 38 and an outlet conduit 39 are provided. As illustrated in Fig. 1, the outlet conduit 39 is connected with cooling coils 49 and 4| surrounding, respectively, the stacks 6 and l and provide for the required cooling of the vacuum pump. It will be apparent that the construction just described provides a very short connection between the device to be evacuated and the intake side of the vacuum pump, which is readily controlled by operation of the solenoid valve, so that the pump need not be subjected to atmospheric pressure during each loading of the compression head with a new device to be evacuated, and the volume of the conduit between the device and the solenoid valve is very small.

As illustrative in Fig. 1, the exhaust or high pressure side of the pump is connected by a conduit 42 with a passage 43 provided in a member 44 which forms a part of a rotary valve. The member 44 is movable with the table I, and the passages, such as passage 43, formed therein cooperate with similar passages 45 formed in a flange 46 of the stationary member 2 of the machine so that the passages 43 and 45 are in registry at each operative position of the machine. It will be understood that there are sixteen pairs of passages, corresponding to the passages 43 and 45, in the complete machine. The passage 45 of the rotary valve is connected by a conduit 41 to a fitting 48 having three openings connected respectively with conduits 49, 59 and 5 l Conduit 49 is connected to the low pressure side of a rough vacuum system which may include booster and vacuum pumps, if desired. This line includes a solenoid valve 52 for purposes which will be described at a later point in the specification. The conduit 59 is connected through a restriction 53 and a solenoid valve 54 to a supply of gas of the type with which the discharge devices are to be charged. The conduit 5i connects with a trap 55 communicating with a U-tube gage 56 which is employed for measuring the pressure in the conduit 41 and which is provided with a plurality of contacts 5861 for controlling the solenoid valve 54 in accordance with the pressure existing in the conduit 41 which is a measure of the pressure in a device 21 as long as valve member 44 is in the open position.

The equipment connected with conduit 41 in the left-hand portion of Fig. 1 is not duplicated at each of the stations, but is provided only at the station at which the devices are to be charged with gas. At all of the remaining stations, as illustrated in Fig. 3, conduits 4'? otherwise corresponding to conduit 41, are connected directly with the rough vacuum system including the booster and backing pumps.

The electrical system for controlling the solenoid valves 52, 54 and the operating coil H? of the valve in the fine pump will now be described. As shown in Fig. 1, a supply of alternating current is provided by conductors 62. Power from this line is supplied to each station on the rotary table I of the machine through slip rings 63 and 64 under the control of a manual switch 65. Power is supplied from the slip rings 63 and 64 by conductors 66 and 61 to the terminals 68 of a heater element (not shown) associated with each of the fine vacuum pumps 3. The conductors and 6'! are also connected with the terminals of the operating coil l8 through a normally closed switch 69 which is cam-operated in accordance with the position of the table I of the machine, and which is in the closed position corresponding to an open position of the valve member l4 in all but the one position of the table of the machine at which the devices to be evacuated are loaded.

The gas charging of the devices 21 is controlled by the contact-making gage 55. To this end the operating coil of the solenoid valve 54 is connected to be energized from the supply conductors 62 through a conductor 19, the contact 6|, the mercury of the U-tube gage 56, contact 58, conductor II and manual switch 12. It will be apparent that when predetermined pressur conditions exist in conduit 41 the mercury in the U-tube bridges contacts 58 and 6| and the circuit of valve 54 is completed, provided the manual switch 12 is in its right-hand position. Gas from the gas supply is admitted to the system under the control of this valve until the circuit is broken as a result of the mercury falling below the lower end of contact 58 in the left-hand arm of the U-tube 56. The additional contacts 59 and 69 extend different distances into the left-hand arm of the U-tube and provide connections for operating the valve 54 at different gas pressures when it is desired to charge the devices 21 to different pressures.

Before putting the system in operation, it is necessary to purge the conduit system including that of the gas charging apparatus and that of the particular movable station which is connected therewith through the rotary valve of the machine. To this end the solenoid valve 52 is arranged to be energized from the circuit 62 througha circuit including conductor 10, the operating coil of valve 52, conductor 13 and manual switch 12- when it is in its left-hand position.

A brief description of the operation of the illustrated embodiment of my invention described above will serve to further emphasize the features andadvantages of my invention. With the switch 85 closed and a device 21, to be evacuated, loaded in each of the stations, switch 12 is thrown to its left-hand position and the machine is placed in operation. Under this condition, the booster and vacuum pumps, as well as the fine pumps, at each of the stations operate to purge the system completely. It will. be understood that the heaters of the pumps are energized and that the movable table I of the machine is periodically indexed by a suitable drive which has been omitted from the drawing and preceding description in the interest of simplicity. After the system has become adequately evacuated, the switch T2 is moved to the right-hand position. The evacuation of the stationary conduit system 41, as described above, is only necessary when starting up the machine. After it has been accomplished the switch 12 is moved to the right-hand position to disable the booster and. backing pump connected with the gas charging conduit 41 and return the control of the solenoid valve 52 to the gage 56. Provided that devices moving into the position illustrated in Fig. 1 of the drawing have previously been adequately evacuated as they occupied the various stations of the machine associated with the conduits 47, the solenoid valve 54 is energized immediately by the bridging of the contacts 58 and 6| of the U-tube 56, permitting gasto flow through the constriction 53 to charge the'conduit 41, flood the pump 3 and charge the discharge device 2'! with a predetermined pressure of gas which, for example, may be xenon, argon or hydrogen. As soon as the pressure in the conduit 41 rises sufficiently, the mercury drops below the lower end of contact 58 and the solenoid valve 54 closes. The pump 3 under these conditions is inoperative to evacuate the device 21 since the pressure to which the device is charged and to which the high pressure side of the pump is raised destroys the pumping action of the fine pump. As the machine indexes to the next position, the switch 59 is opened by a suitable cam on the machine and the solenoid valve member I4 is closed to shut off the low pressure side of the pump 3. In this next position. it will be apparent that the conduit 42 and. the pump 3 are evacuated by the booster and backing vacuum pumps associated with th stationary conduit 41 at that station. The discharge device is removed from the machine after sealing oii the tabulation 28 and a new device is loaded into the machine. It will be readily appreciated that when the machine indexes to the next position and solenoid valve I4 opens, only the air within the unevacuated discharge device 21, which has just been loaded, and the air in the conduit between valve I4 and the compression head are required to be handled by the fine pump 3. machine and prevents contamination of the fluid in the pump so that pumps employing an organic liquid may be used.

It will be apparent that the apparatus described above provides for the high speed evacuation of This speeds up operation of the devices on automatic machinery, while protecting the fine pump from large amounts of air. It is also. apparent that the gas presure to which the devices are charged is automatically controlled, with the result that uniform products are produced and'the gas, which is a large item of expense, is not wasted.

While I have shown and described a particular embodiment. ofmy invention, it will be apparent to those skilled in the art that changes and modifications may be made without departing from the features of my invention, and. I, therefore, aim in the appended claims to cover all such changes and modifications as fall within the true; spirit and'scope of my invention.

' What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In combination, a movable support, a vacuum pump mounted on said support, means sup ported from said pump for supporting a device to be evacuated in communication with the intake side of said pump, valve interposed between said pump and said means and including a magnetic actuating member, a coil surrounding said member, and means for controlling the energization of said coil to control the operation of said valve.

In combination, a movable support, a vacuum pump mounted on said movable support and having inlet and outlet passages, a fitting for supporting a device to be evacuated and mounted infixed relation to said pump, a short conduit connecting said fitting and the inlet passage of said pump, a valve within said conduit for controlling the eonnection of said pump with said fitting, a coil surrounding said conduit, and means for controlling the energization of said coil to control the operation of said valve.

3, In combination, a vacuum pump having a vertical stack providing at its upper end an inlet passage, a compression fitting supported from said pump and including a vertical passage adapted to receive a part of a device to be evacuated, a transverse conduit connecting the vertical passage of said fitting with the inlet passage of said pump, the vertical passage of said fitting extending below said transverse conduit to provide a receptacle for foreign matter dropping from said fitting, and a solenoid valve between said fitting and the inlet passage of said pump for controlling communication between said pump and said fitting. i. In combination, a movable support, a vacuum pump of the vapor diffusion condensation type mounted on said support and including a conduit connected to the low pressure side thereof, a compression fitting for supporting a device to be evacuated connected with said conduit, a valve within said conduit including an actuating member, a solenoid surrounding said conduit for actuating said valve, and switch means connected in circuit with said solenoid and operable in accordance with the position of said movable support for controlling the operation of said valve.

5. In combination, a movable support, a vacuum pump mounted on said support, a stationary support, a pliirality of stationary conduit systems, valve means having complementary ports mounted on said movable and stationary supports for connecting said vacuum pump with a different one of said conduit systems in each of a plurality of positions of said movable support, one of said conduit systems including a source of gas and a solenoid valve for controlling the admission of gas to said conduit system, and means responsive to the pressure of said conduit system for controlling the operation of said solenoid valve to determine the amount of gas admitted to said system.

6. In combination, a movable support, a vacuum pump mounted on said support andincluding an inlet passage, means connected with said passage for supporting a device to be evacuated, a stationary support, a plurality of stationary conduit systems, valve means including complementary ports mounted on said movable and stationary supports for connecting said vacuum pump with a different one of said conduit systems in each of a plurality of positions of said movable support, one of said conduit systems including a source of gas and a solenoid valve for controlling the admission of gas to said conduit system, and means responsive to the pressure within a device being evacuated for controlling the operation of said solenoid valve to determine the amount of gas admitted.

7. Evacuating and gas charging apparatus comprising in combination a stationary support, a plurality of radially spaced conduit systems connected with said support and each including evacuating apparatus, a movable support positioned on said stationary support including a conduit system communicating respectively with successive ones of the conduit systems associated with the stationary support in successive operating positions of the movable support, a vacuum pump mounted on said movable support and conneoted with the conduit system of said movable support, a compression fitting for supporting a device to be evacuated including a passage communicating with the low pressure side of said Vacuum pump, a supply of gas communicating with one of the conduit systems associated with the stationary support, a solenoid valve for controlling the connection of said supply of gas with said conduit system, means responsive to the pressure in the conduit system with which said supply of gas is associated for controlling the operation of said solenoid valve to charge the conduit system to a predetermined gas pressure, and means for preventing operation of said solenoid valve until the conduit system has been evacuated to a predetermined pressure.

8. An evacuating and gas charging system comprising a plurality of stationary conduit systems each including pumping apparatus for maintaining a rough vacuum, a movable support, a series fluid circuit including a support for a device to be evacuated, a fine vacuum pump and a conduit carried by said movable support, selector valve means operated in response to the position of said movable support for connecting the conduit of said series fluid circuit with successive ones of said conduit systems, a supply of gas,

means connecting said supply with one of said stationary conduit systems between said selector valve means and said pumping apparatus including a solenoid valve, and pressure responsive means for opening said solenoid valve when said selector valve connects the conduit of said series fluid circuit with said one of said conduit systems to charge a device connected to said support to a predetermined gas pressure and for maintaining said solenoid valve closed when the pressure in said one system exceeds a predetermined value.

9. An evacuating and gas charging system comprising a plurality of stationary conduit systems each including pumping apparatus for maintaintaing a rough vacuum, a movable support, a series fluid circuit including a support for a device to be evacuated, a fine vacuum pump and a conduit carried by said movable support, selector valve means operated in accordance with the position of said'movable support for connecting the conduit of said series fluid circuit with successive ones of said conduit system, a supply of gas, means connecting said supply with one of said stationary conduit systems between said selector valve means and said pumping apparatus including a solenoid valve, and pressure responsive means for opening said solenoid valve when said selector valve connects the conduit of said series fluid circuit with said one of said conduit systems to charge a device connected to said support to a predetermined gas pressure.

10. In combination, a movable support, a vacuum pump mounted on said support and including a conduit connected to the low pressure side thereof, a fitting for supporting a device to be evacuated connected with said conduit, a valve within said conduit including an actuating member, a solenoid surrounding said conduit for moving said actuating member to operate said valve, means for controlling the energization of said solenoid in accordance with the position of said movable support for controlling the operation of said valve, said valve being located in close proximity to said fitting to minimize the amount of air admitted to said pump as a result of loading of a device to be evacuated in said fitting.

CHARLES T. DE GROAT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,651,865 Blake et al Dec. 6, 1927 1,831,935 Walker Nov. 17, 1931 2,247,513 Marshaus July 1, 1941 2,254,905 Mullan Sept. 2, 1941 

